The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Substrate processing systems may be used to perform deposition and/or etching of film on a substrate such as a semiconductor wafer. Substrate processing systems typically include a processing chamber with a substrate support such as a pedestal, an electrostatic chuck, a plate, etc. A substrate such as a semiconductor wafer may be arranged on the substrate support. In chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), atomic layer deposition (ALD) or PEALD processes, a gas mixture including one or more precursors may be introduced into the processing chamber to deposit or etch a film on the substrate.
Some processes use a gas distribution device such as a showerhead. The gas distribution device may include a faceplate with a plurality of circular holes. The circular holes are arranged in a pattern to provide a desired gas flow. Process gases are supplied to a cavity defined in the gas distribution device and is disbursed by the circular holes of the faceplate over the substrate.
In PECVD and PEALD, radio frequency (RF) plasma may be used to activate chemical reactions. For example, a capacitively coupled plasma (CCP) generator may be used to generate plasma in the processing chamber. The plasma may be struck in a space between the faceplate of the gas distribution device and the pedestal. The faceplate of the gas distribution device may act as one electrode of the CCP generator.
When plasma is used during substrate processing, some parasitic plasma may also be generated in the processing chamber. For example only, hollow cathode discharge (HCD) is one form of parasitic plasma that may occur in the circular holes of the faceplate of the gas distribution device. HCD may be detrimental to hardware (specifically, the electrode) because HCD dissipates significant power within a small volume.